Congenital heart malformations are the most common birth defects, affecting 0.8-0.9% of all live births. The most frequently occurring group of serious congenital heart disease (CHD) lesions is the Functional Single Right Ventricle (FSRV) malformations, including hypoplastic left heart syndrome. Survival beyond early infancy, once impossible for this patient group, has improved markedly in the past 30 years due to innovations and refinements in surgical and perioperative care. The Norwood operation, the first step in the 3-stage surgical palliation for these children is now performed at selected pediatric cardiac centers with hospital survival rates >90%. However, the rate of death between hospital discharge following the Norwood operation and the initiation of the stage II operation at 4 to 6 months of age remains unacceptably high at up to 20%. Data from two small, single center, case series suggest that a comprehensive home monitoring program (CHMP) conducted from Norwood discharge until the stage II operation can significantly reduce interstage mortality. In a CHMP, digital scales and pulse oximeters are distributed to families at Norwood hospital discharge and parental caregivers are instructed on daily measurements. If pre-determined oxygen saturation or weight gain thresholds are breached, patients are evaluated by a physician within 24 hours. While a CHMP is intuitively attractive, sound evidence-based data are lacking, and the potential for negative implications related to actions on 'false positive data', such as invasive testing or earlier stage II operation, have not been systematically evaluated. In addition, lack of reimbursement from third party payers for this promising, but unproven, therapy remains a significant barrier to widespread implementation across congenital heart centers. As part of the University of Michigan Congenital Heart Center application to the PHN, the proposed study involves a multicenter randomized clinical trial to determine if a CHMP improves interstage survival for children with FSRV malformations, and to evaluate potential medical consequences and the financial costs of this home monitoring program. RELEVANCE: FSRV lesions are the most common group of severe congenital heart malformations, affecting - 1000 newborns in the US each year. Hospital mortality for the Stage I, Norwood operation has improved dramatically in recent years; the period between hospital discharge and the stage II operation is now the highest risk period for these children. The proposed trial targets this high risk time for children with FSRV.